Abstract:

A folder and method for folding plastic bags includes at least one folding
station. The folding station has a folding point where an input, an
output and a storage portion meet. The bag travels in the input portion
in a different direction than in the storage portion. The output
direction is substantially the same as the input direction. A turning air
source is disposed to direct the bag into the storage portion and an air
source is disposed to direct the bag into the output section. A fin helps
guide the bag into the output portion. A turning roll disposed above the
turning point, and imparts motion to the bag, generally in the storage
direction. A second folding station, similar to the first, is downstream
the first folding station. The output direction for the first station is
the same as the input direction for the second station, and the bag path
between the first and second folding stations is substantially linear. A
separator located upstream of the folder includes a separator nip formed
by separator rolls that are in, and remain in, the film path in one
embodiment. A slow-down section includes servo-driven slow down rolls
with projections there on.

Claims:

1. A folder for folding a bag comprising;an infeed section disposed to
feed bags to a subsequent station; anda folding station, disposed to
receive bags from the infeed section, and includingan input portion, in
which the item travels in an input direction which is towards a first
folding point, wherein an original leading edge of the item is traveling
in the input direction as it reaches the first folding point;an output
portion, in which a newly formed leading edge of the item travels in an
output direction which is away from the first folding point during at
least part of the time that an original trailing edge travels in the
input direction; anda leading edge storage portion, in which the entire
original leading edge of the item travels in a storage direction before
the newly formed leading edge travels in the output direction, wherein
the input, output and storage portions meet at the first folding point,
and wherein the original trailing edge does not travel in the storage
direction;wherein the input direction and the output direction are in a
common plane, and further are different from the storage direction.

2. (canceled)

3. The folder of claim 1 wherein the input direction is substantially
horizontal.

4. The folder of claim 3 wherein the storage direction has a downward
component.

5. The folder of claim 4 wherein the storage direction is less than about
30.degree. from vertical.

6. The folder of claim 1, wherein the item is a bag, and further including
a turning air source disposed to direct the bag into the storage portion.

7. The folder of claim 6 further including a folding air source disposed
to direct the bag into the output section.

8. The folder of claim 7 further including a fin disposed to help guide
the bag into the output portion.

9. The folder of claim 8 further including a turning roll disposed above
the turning point, and further disposed to impart motion to the bag,
generally in the storage direction.

10. The folder of claim 1 further including at least a second folding
station downstream of the first folding station, wherein the second
folding station comprises:a second input portion in which the item
travels in a second input direction;a second output portion, in which the
item travels in a second output direction; anda second leading edge
storage portion, in which the item travels in a second storage direction,
wherein the second input, output and storage portions meet at a second
folding point; andwherein the second input direction is different from
the second storage direction.

11. The folder of claim 10, wherein the item is a bag, and wherein the bag
path between the first and second folding stations is substantially
linear.

12. The folder of claim 1 further including a separator located upstream
of the folder.

13. The folder of claim 12 wherein the separator includes a separator nip
formed by separator rolls, wherein the separator rolls are in, and remain
in the path of the item.

14. The folder of claim 12 wherein the separator rolls are servo-driven
rolls.

15. The folder of claim 12 wherein the item is a bag, and at least one
separator guide acts to guide the bag through at least a part of the
separator, and at least one folder guide acts to guide the bag through at
least one part of the folder, and wherein the separator guide overlaps
the folder guide.

16. The folder of claim 12 wherein the guides are ropes.

17. The folder of claim 16 wherein the guides are belts.

18. The folder of claim 12 wherein a guide is disposed to guide the item,
and a guide return roll is provided out of the film path.

19. The folder of claim 1 including a slow-down section located downstream
of the folding station.

20. The folder of claim 19 wherein the slow-down section includes two
servo-driven rolls, each with at least one projection thereon, disposed
to contact the item.

21. The folder of claim 20 wherein each servo-driven roll has two
projections.

22. A folder for folding a bag, including a first folding station
comprising;an input means for receiving the bag, in which the bag travels
in an input direction toward a first folding point, wherein an original
leading edge of the bag is traveling in the input direction as it reaches
the first folding point;an output means for outputting the bag in which a
newly formed leading edge of the bag travels in an output direction away
from the first folding point during at least part of the time that an
original trailing edge travels in the input direction; anda leading edge
storage means for temporarily storing a leading part of the bag, in which
the entire original leading edge of the bag travels in a storage
direction before the newly formed leading edge travels in the output
direction, wherein the input, output and storage means meet at the first
folding point and wherein the original trailing edge does not travel in
the storage direction;wherein the input direction and the output
direction are in a common plane and further are different from the
storage direction.

23. (canceled)

24. The folder of claim 22 wherein the input direction is substantially
horizontal.

25. The folder of claim 24 wherein the storage direction has a downward
component.

26. The folder of claim 22 further including a turning air means for using
air to direct the bag into the storage portion.

27. The folder of claim 26 including a folding air means for using air to
direct the bag into the output section.

28. The folder of claim 27 further including a turning roll means,
disposed above the turning point, for imparting motion to the bag
generally in the storage direction.

29-44. (canceled)

Description:

FIELD OF THE INVENTION

[0001]The present invention relates generally to the art of making bags
from a plastic film. More specifically, it relates to a method and
apparatus for folding and separating bags.

BACKGROUND OF THE INVENTION

[0002]There are many uses and designs for plastic bags. Such bags are
typically manufactured from plastic films, and there are many known
machines for automatically making bags from such a film. Some bag making
machines create bags on a continuous strip of plastic film or web
(typically a flattened tube or a continuous folded sheet. Bags are made
by forming seals (typically transverse to the machine direction or along
the side of the film). Adjacent bags are separated from one another by
forming a perforation parallel to (and preferably close to) the seal. The
perforation allows the bags to be separated (either manually or in a
downstream device).

[0003]Bag making machines often include equipment that separates adjacent
bags and then folds and stacks the separated bags. Bags are separated in
some prior art machines by operating a downstream nip at a higher speed
than the speed at which the upstream film or web is travelling. When the
perforated film or web encounters the downstream rollers (often called
separation rollers), the higher speed of the rollers pulls the web,
thereby tearing along the perforations. The separation rollers are
typically mounted on a cam, cylinder, or some other device, which
intermittently brings the separation rollers into contact with each other
and the film, to separate adjacent bags. This sort of separation was
adequate at lower speeds, but it often limited the operating speed.

[0004]An example of the intermittent contact type of prior art separator
is found in U.S. Pat. No. 5,388,746 issued Feb. 14, 1995. This is a
complex design and the oversped rolls are operated at a constant speed,
thus the available control is limited.

[0005]Many prior art separators include an infeed nip formed by driven
rolls. This results in a linear speed difference between the ropes and
the rolls. Prior art separators also often include a zone where the bag
is not between ropes, as the separated bag passes from the separator to
the downstream section (such as a folder). The bags are not controlled at
that gap, and can jam the machine. Additionally, prior art machines
typically have ropes which are returned by rolls in the film path. Thus,
a pinch point that can catch the film or bag is created between the rope
and the roll. This can create jams in the machine.

[0006]After the bags have been separated it is common for them to be
provided to a folder that folds the bags one or more times. Generally, a
folder includes a number of folding sections, wherein the maximum number
of folds available is equal to the number of folding stations.

[0007]U.S. Pat. No. 5,388,746, issued Feb. 14, 1995, shows a prior art
folder. The folder shown therein includes three folding sections located
downstream of a separator. The separated bags are traveling in a downward
direction as they approach each folding station. The leading edge of the
bag passes a folding nip, and then the middle of the bag is blown in a
direction almost perpendicular to the original path direction (close to
horizontal). The bag is grabbed in a nip and then folded. The bag
continues on in a substantially horizontal direction until it approaches
the second folding station. Then, the bag must be redirected in a
downward direction where the second folding station operates
substantially as did the first folding station. A third folding station
(also mounted such that the bag must enter it in a downward direction) is
also provided.

[0008]The arrangement shown in U.S. Pat. No. 5,388,746 is relatively
complex, and the bags make two turns for each fold. The bags are
travelling in one direction entering the folding point, and exit the
folding station in a different direction. Thus, the momentum of the
trailing end of the bag is not useful in helping to crease the new fold
bag because of the different directions. The extra turns in the path of
the bags also make handling the bags more difficult and more likely for
jams or other failures of the process.

[0009]Moreover, the path of the return ropes is such that access to the
folding stations for service, adjustment etc. is relatively difficult.
Also, because the bags are not held by ropes or nips immediately prior to
the folding point, there is an opportunity for a bag to be skewed or
improperly folded.

[0010]After the bags have been folded they typically are slowed down so
that they may be more easily managed in downstream processing stations.
One prior art method for slowing down folded bags is a passive system,
wherein the bags enter a slow down section, and are allowed to gradually
slow down to rope speed. One problem with this passive slowing down is
that the bags can easily become skewed from the machine direction, and it
is hard to properly control the bag speed.

[0011]Another prior art slow down section includes a downward discharge.
The bag falls in the downward discharge into two belts that form a V. The
apex of the V is a nip such that the bag falls into that nip and is
slowed down by the speed of the belts. One problem with this arrangement
is that the bag can bunch up as it enters the nip.

[0012]Another prior art method is shown in U.S. Pat. No. 4,073,223, issued
Feb. 14, 1978. This method uses a rudimentary form of control wherein a
pair of rollers are operating at a slower speed than the upstream machine
speed. The rollers have bars mounted thereon, arranged such that when the
rollers rotate, the bars come in contact with one another. The rollers,
are turned such that momentary contact is made between the bars and the
trailing edge of the bag, thereby slowing the bag down. One problem with
this system is that the rotation of the rollers is a continuous motion
system which is not indexed to each bag. Thus, it is difficult to
maintain the proper timing over a long period of operation of the
machine. Also, there are other timing related problems which occur at
certain speeds and bag lengths.

[0013]Accordingly, it is desirable for a separator and folder to include a
separator that properly separates adjacent bags. Additionally, the
separator should be designed such that bags are not likely to flutter as
they leave the separator. Preferably, such a folder and separator should
also provide for continuous holding of separated bags to prevent fly
back.

[0014]The folding section should preferably be configured without
unnecessary turns so as to avoid unnecessary complexity and cost.
Preferably, it should be designed such that in the event less than the
maximum number of folds is being implemented the bag does not have to
undergo turns. Improperly folded bags should be discharged in downward
direction so they do not cause jams. The folding section should be easily
accessible from the top. Also, the folding section should utilize the
momentum of the bag prior to the folding to help fold the bag.

[0015]A slow down section preferably includes a slow down nip that is easy
to control and can be precisely aligned with the bags.

SUMMARY OF THE PRESENT INVENTION

[0016]According to a first aspect of the invention a folder, and method
for folding, plastic bags includes at least one folding station. The
folding station has a folding point at which an input portion, an output
portion, and a storage portion meet. The bag travels in an input
direction in the input portion, in an output direction in the output
portion, and in a storage direction in the storage portion. The input
direction is different from the storage direction.

[0017]In one embodiment the output direction is substantially the same as
the input direction. In another the input direction is substantially
horizontal. The storage direction has a downward component in an
alternative embodiment. The storage direction is preferably less than
30° from vertical.

[0018]A turning air source is disposed to direct the bag into the storage
portion in another embodiment. A folding air source is disposed to direct
the bag into the output section in another embodiment. A fin is disposed
to help guide the bag into the output portion in an alternative. A
turning roll is disposed above the turning point, and imparts motion to
the bag, generally in the storage direction, in yet another embodiment.

[0019]The folder includes a second folding station downstream of the first
folding station in another embodiment. The second folding station is
configured like the first folding station.

[0020]The output direction for the first station is the same as the input
direction for the second station, and the bag path between the first and
second folding stations is substantially linear in another embodiment.

[0021]The folder includes a separator located upstream of the folder in
another alternative. The separator includes a separator nip formed by
separator rolls that are in, and remain in, the film path in one
embodiment. The separator rolls are preferably servo-driven rolls.

[0022]The separator includes guides, such as ropes or belts, that guide
the bag through at least a part of the separator. The folder includes
guides, such as ropes or belts, that guide the bags through at least one
part of the folder. The separator guides overlap the folder guides. The
guides have return rolls located out of the film path in another
embodiment.

[0023]The folder includes a slow-down section located downstream of the
folding station in an alternative. The slow-down section preferably
includes two servo-driven rolls, each with at least one projection
thereon, disposed to contact the bags. In one embodiment each
servo-driven roll has two projections.

[0024]Other principal features and advantages of the invention will become
apparent to those skilled in the art upon review of the following
drawings, the detailed description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a diagram of a folder, separator, and slow down section
constructed in accordance with the present invention;

[0026]FIG. 2 is a diagram of the separator of FIG. 1;

[0027]FIG. 3 is a diagram of the folder and slow down section of FIG. 1;
and

[0028]FIG. 4 is a detailed diagram of a folding point on a folding station
of FIG. 3.

[0029]Before explaining at least one embodiment of the invention in detail
it is to be understood that the invention is not limited in its
application to the details of construction and the arrangement of the
components set forth in the following description or illustrated in the
drawings. The invention is capable of other embodiments or of being
practiced or carried out in various ways. Also, it is to be understood
that the phraseology and terminology employed herein is for the purpose
of description and should not be regarded as limiting. Like reference
numerals are used to indicate like components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030]While the present invention will be illustrated with reference to a
particular separator, folder and slow down section used for plastic bags,
it should be understood at the outset that the invention can also be
employed using other components and designs, one or more of the
separator, folder and slowdown section described herein, or for pliable
items other than bags.

[0031]Generally, the preferred embodiment includes a separator that
receives a continuous film of bags. The bags are formed by placing seals
on the film, and adjacent bags are also separated by perforations. Bags
are separated in the separator, and then provided to a folder which
includes a plurality of folding stations. The bags are folded by each
folding station (up to three times in the preferred embodiment) after
leaving the folding station. The bags are then provided to a slow down
unit.

[0032]Referring now to FIG. 1 a bag machine 100 is shown and constructed
in accordance with the preferred embodiment. Machine 100 includes a
separator 102, a folder 104, and a slowdown station 106. Generally, a
film of bags is provided to separator 102 from an upstream bag machine
that forms the bag, or from a roll of previously formed bags. Top and
bottom ropes or belts are provided throughout machine 100 in the
preferred embodiment. Generally, at speeds greater than 400 feet per
minute, top and bottom ropes are needed to prevent the film from folding
back (fly-back) or from having fatal fluttering.

[0033]The speed of separator 102 is controlled to follow the speed at
which the film is being fed to separator 102. Separator 102 includes a
nip with over speed rolls that speed up the leading edge of a bag,
thereby separating the bag from the film. After the bags are separated
they are provided to folder 104. Folder 104 includes three folding
stations (described in detail below), an inspection station and ironing
rolls. Each folding station can impart one fold in the machine direction
of the bag. Thus, the final bag may be folded up to three times (and will
be 1/8 the length of the incoming bag). However, it is possible to not
use one or more of the folding stations in the preferred embodiment. The
path the bag takes through the folding stations is in a single plane,
except where the leading edge is temporarily diverted downward.

[0034]The bags are provided to slow down section 106 after folding. Slow
down section 106 includes, in the preferred embodiment, slow down rolls
and a corrugator. Slow down section 106 will be described in detail
below. Machine 100 is generally driven by a single belt, except for the
servo-drives described below, and (in one embodiment) the slow down guide
ropes.

[0035]Separator 102, shown in detail on FIG. 2, includes an infeed section
201 which is comprised of a plurality of dancer rolls 202. Dancer rolls
202 are used to match the speed of machine 100 to the speed of the
upstream bag machine in a conventional manner.

[0036]A pair of rope idlers roils 206 and 207 receive the film of bags
from dancer rolls 202. Rolls 206 and 207 do not form a nip. Thus, the
speed of the ropes can he maintained at the speed of the main nip and the
film. Specifically, the ropes can ride in grooves in the main nip roll,
and thus the ropes and main nip rolls can have the same linear speed. A
pair of rolls 208 and 209 form the main nip, and drive the film into the
separator section (at machine speed).

[0037]After the film passes through the main nip it is carried by a
plurality of ropes and/or belts 210 and 218 to a servo-driven separation
nip formed by a pair of servo-driven rolls 212 and 213. The servo driven
separation nip is controlled such that rolls 212 and 213 are
intermittently oversped to separate adjacent bags. The control is
performed by a controller such as a microprocessor, digital signal
processor, or PLC. The PLC or controller uses an input device to sense
the location of the leading edge of the film of bags in the preferred
embodiment.

[0038]Ropes 210 and 218 extend from the rollers 206 and 207 through
separator 102 and into folder 104 (described below). Ropes are used above
the film to help prevent flutter and fly back of the film, and to help
control the film as it is separated.

[0039]An electric eye 220 is located between the main nip and the
servo-driven separation nip formed by rolls 212 and 213. Electric eye 220
senses gaps betweens the bags and is used to control the timing.
Initially, the film of continuous bags is fed through machine 100. When
the operator activates the folding function, the servo-driven separation
nip is oversped by about 10%, thereby separating the leading bag from the
following bag, and creating a gap between bags.

[0040]When the gap between bags is sensed by electric eye 220, the
servo-driven separation nip is slowed down to slightly under machine
speed, to pull out wrinkles in the separated bags. After a brief slow
period the separation nip is brought back up to line speed. Also, a
counter in the PLC or controller begins counting, (when the gap is
sensed), which effectively measures distance. After a sufficient length
of bag has passed (as determined by the counter) the next perforation has
moved into position for separation (just past the main nip). Electric eye
220 is enabled to detect gap and the servo driven separation nip again is
oversped to separate the leading bag from the following bags (again
creating a gap for electric eye 220 to sense). Then the separation nip
returns to underspeed, taking out wrinkles, and the process is again
repeated.

[0042]A plurality of rolls 223, 224, 225, and 226 are provided to create
the transition between separator 102 and downstream folder 104. Rolls 224
and 223 guide and return the ropes serving the first folding station in
folder 104. Rolls 226 and 225 return ropes 210 and 218 (i.e. they are
return rolls) to section 102. It may be seen that there is an overlap
between the ropes in the folder and separator sections in the preferred
embodiment. This avoids the gap between sections common in prior art
machines. The overlap helps to guide and drive the bags as they move from
the separator to the folder.

[0043]Generally, rolls 225 and 226 are located away from the film path.
Thus, they relocate the pinch point from being in the film path (either
above or below the film path depending on whether the ropes are above or
below the film) to out of the film path.

[0044]After the bags have been separated by rolls 212 and 213, the bags
pass rolls 223-226 and enter folder 104. Generally, folder 104 includes a
plurality of folding stations 301, 302, and 303, and an inspection
section 304. Folders 301-303 are generally configured like one another,
and function in a similar manner. A plurality of ropes 330 are provided
above the path of the bags and extend throughout all of folder 104,
including folding station 301-303. Preferably, folder 104 is run about 3%
over speed to pull out wrinkles and maintain a gap between bags.

[0045]The bags in the folder 104 are carried by a plurality of sets of 3/4
inch wide flexible belts 306, 307 and 308. One set of belts is provided
for each folding station. Each belt is a flat belt with a V-guide on the
back. The belt top has a flat surface 3/4 inches wide on which the film
rides. The V-guide tracks the belt around the various rolls.

[0046]Static pinner 310 is located between the beginning of the folding
section and the first folding point. Static pinner 310 creates a known
(and controllable) level of static. This is preferable to static levels
that vary. A photo eye 312 detects the leading edge of each bag, and is
used to control the process of turning on and off air that is used to
control the bag in the folder.

[0047]Generally the operation of folding stations, 301, 302, and 303 is
such that the bags enter the folding station traveling in a horizontal
path. Each folding station has a folding point 315-317. A source of air
is located above the ropes at each folding point (315 e.g.) and directs
the leading edge of the bag in the downward direction, following the
guide belts 306-308. The substantially downward direction is a few
degrees off of vertical in the preferred embodiment, although it may vary
in alternative embodiments.

[0048]After the leading edge of the bag has traveled downward a distance
sufficient so that the midpoint of the bag has reached the folding area
an air nozzle located below the guide belts blows the middle of the bag
into a nip. The section where the leading edge of the bag temporarily
travels downward is referred to herein as the leading edge storage
portion because the leading edge of the bag is temporarily "stored"
therein, while the fold is being created.

[0049]The nip grabs the middle of the bag and pulls the bag away from the
folding area. The bag is pulled in a horizontal direction. What had been
the leading edge of the bag is pulled upward while the former trailing
edge of the bag is pulled horizontally. The forward momentum of the tail
of the bag is in the horizontal direction, and it helps push film into
the fold nip which makes folding easier and more consistent. After the
fold the bag is now configured such that what had been the leading edge
of the bag joins the what had been the trailing edge of the bag to form
the trailing edge (because the bag has been folded it has multiple
trailing edges). What had been the middle of the bag becomes the leading
edge, with a fold therein.

[0050]The path the bag travels as it approaches the folding point lies in
a plane. That plane defines the input direction. Similarly, the plane in
which the leading edge, travels while being stored defines the storage
direction. The output direction is defined by the plane in which the bag
travels as it leaves the folding point. The output and input directions
are substantially the same, but different from the storage direction, in
the preferred embodiment.

[0051]Referring now to FIG. 4, the folding point for folding station 301
is shown in detail (the folding point for stations 302 and 303 are
arranged in an identical manner in the preferred embodiment). A turn air
pipe 401 is located at folding point 315. Turn air pipe 401 is preferably
a stationary pipe with a plurality of idler pulleys 402 on it. A
plurality of nozzles 403 are screwed into pipe 401 between rollers 402.
Thus, while the idler pulleys rotate with ropes 330, nozzles 403 remain
in a fixed position. Nozzles 403 are positioned to blow the leading edge
of the bag downward past a turning roll 405 (comprised of a plurality of
idler pulleys). A set of ropes 332 (FIG. 1) are provided substantially
parallel to belt 306 in the downward travelling portion (the storage
portion) section to help reduce adverse flutter. The position of belts
306 and airpipe 401 is such that, in the preferred embodiment, the
leading edge of the bag receives a slight downward push from the ropes to
aid the air in directing the leading edge of the bag in the storage
direction. The downward deflection is omitted in alternative embodiments.
When the leading, edge of the bag has traveled downward such that the
midpoint of the bag has reached turning roll 405 nozzles 403 are turned
off. The distance is determined using electric eye 312 and a counter in
the PLC or controller.

[0052]A plurality of folding nozzles 407 are screwed into a fold air pipe
406. Nozzles 407 are turned on when nozzles 403 are turned off. Nozzles
407 are disposed within gaps between the idler pulleys 405, which are
mounted on air pipe 406. Nozzles 407 blow air from the radial direction
of pipe 406 in the preferred embodiment. Air blown in this direction
draws air from both sides of the pipe and helps move the folded bag in
the desired direction. The bag is then grabbed by rolls 408 and 409, and
pulled downstream (in a substantially horizontal direction).

[0053]A fin 410 prevents the edges of the bag from being blown up between
ropes 330 and into the upper roll. Fin 410 is an L shaped piece of metal
mounted near air pipe 401.

[0054]Alternative embodiments include adjusting the angle of the nozzles
with respect to the axis of pipe 406, and/or using varying diameter
nozzles along the transverse direction (or cross machine direction) of
pipe 406. Proper selection of the angle and diameter can help control the
edge of the bag to avoid folding the corner of the bag under (called a
dove tail). Dove tails can be caused when the edge of the bag is too far
from a nozzle, for example, and the edge folds under. Angled nozzles
and/or different diameter nozzles can help control the edges of the bag.

[0055]Subsequent folding sections are cascaded together so that successive
folds can be made. Each section operates as did section 301. A fold may
be skipped by leaving turn nozzles 403 off and folding nozzles 407 on,
thus creating an airbridge in the gap. If a section is to be skipped, it
should not be the first section because the first fold section is longer
(and can handle an unfolded bag).

[0056]The downward travel paths (storage portion) are at a slight angle of
approximately 8 degrees to vertical, in the preferred embodiment. This
helps to avoid air turbulence on the leading edge of the bag traveling
downward. Alternatives provide for angles of between 0-15 degrees, or as
high as 30 degrees from vertical. Other alternatives include even greater
(or negative angles). Generally, increasing the angle requires an
increase in the size of the gap between the sections. A static pinner.350
is provided after section 301. Static pinner 350 helps hold the bag in
position against the belt, as well as helps hold the folded bag together,
and it helps the folded bag lay flatter.

[0057]An inspection section 304 is provided and looks much like a folding
station. However, inspection section 304 either creates an air bridge, or
it blows a bag downward to reject the bag: it does not fold bags. An
electric eye 325 is used to sense the length of the bag. If the bag is
too long (meaning the fold was either missed or not close enough to
folding the bag in half to be acceptable) the bag is rejected.

[0058]Following the rejection section there is a pair of ironing rolls 335
and 336. Ironing rolls 335 and 336 form a smooth nip and take out
wrinkles. They also help the folded bag lay flatter.

[0059]A slow down servo-nip is formed by two servo-driven rolls 361 and
362 and is located after ironing rolls 335 and 336. These rolls, which
operate at a speed slower than the machine speed, have a pair of
protrusions, projections, or pucks 365, which meet in the path of the bag
when properly aligned. Pucks 365 are located generally side to side
toward the centerline of the film web, so that the bag is "grabbed" near
the centerline and skewing or cocking is avoided. Rolls 361 and 362
includes two sets of two pucks 180 degrees apart, so that each revolution
provides for slowing down two bags. Each puck is about an inch long in
the machine direction (so that it goes with the travel of the bag for
about an inch), and an inch wide (so it does not grab the entire bag).
The preferred slow down speed is to about 300 feet per minute, from a
machine speed up to 1000 feet per minute (typically about 700 feet per
minute).

[0060]The servo-drive has a simple motion profile wherein the initial
position is just prior to grabbing the bag. When the bag is sensed the
servo-nip grabs the tail end of bag for the inch of travel the pucks 365
contact the bag, and slows the bag down to the nip speed. Then rolls 361
and 362 increment back to the initial position. Alternatives include
using a different number of pucks, circumferentially or transversely,
depending on your particular wants and desires for the machine. Also, the
motion profile could be continuous or in a registration mode.

[0061]Following the slow down nip is a corrugator 370 that stiffens the
bag in a known manner.

[0062]Numerous modifications may be made to the present invention which
still fall within the intended scope hereof. Thus, it should be apparent
that there has been provided in accordance with the present invention a
method and apparatus for folding, separating and slowing down bags that
fully satisfies the objectives and advantages set forth above. Although
the invention has been described in conjunction with specific embodiments
thereof, it is evident that many alternatives, modifications and
variations will be apparent to those skilled in the art. Accordingly, it
is intended to embrace all such alternatives, modifications and
variations that fall within the spirit and broad scope of the appended
claims.